Field of the Invention
The present invention relates to a radiation imaging apparatus and a radiation imaging system each obtaining, as an image, the intensity distribution of radiation that has transmitted through an object.
Description of the Related Art
Conventionally, a radiation imaging system has been commercialized, which irradiates an object with radiation from a radiation irradiation source, digitizes a radiation image as the intensity distribution of the radiation that has transmitted through the object, and generates a clearer radiation image by performing required image processing. In such a radiation imaging system, synchronous communication is performed between a radiation imaging apparatus and a radiation generation apparatus, and the radiation imaging apparatus transfers obtained radiation image data to an image processing apparatus such as a personal computer for image processing or saving. The image processing apparatus causes a display apparatus such as a display to display the radiation image data that has undergone the image processing.
On the other hand, when radiation imaging apparatuses capture radiation images, individual characteristics of the respective radiation imaging apparatuses need to be corrected. Japanese Patent Laid-Open No. 11-113889 has disclosed an arrangement in which sensor characteristic information such as information (sensitivity correction information) for correcting the sensitivity difference between respective image sensors and defective pixel information is stored in a non-volatile storage unit included in a radiation imaging apparatus. It becomes possible to read out these pieces of information when necessary by storing them in the non-volatile storage unit.
The sensitivity correction information and the defective pixel information may change over time. It is therefore desirable that sensor information is obtained again periodically and the newly obtained information is stored in the non-volatile storage unit. In this case, if only the latest information is always stored, a case may occur in which a correct image cannot be obtained when the newly obtained information has some defect.
The present invention provides a technique capable of storing the first sensor characteristic information of a radiation sensor unit obtained based on radiation irradiation from the first radiation source and the second sensor characteristic information obtained after the first sensor characteristic information based on radiation irradiation from the second radiation source different from the first radiation source such that the first sensor characteristic information can be used when the second sensor characteristic information has some problem.